The present invention relates to fittings for mounting the wing of a window or door to its frame and more particularly to swing-tilt fittings for windows and doors which permit the wing of the window or door to be tilted about a bottom axis or swung about a side axis with respect to the frame.
Conventionally, swing-tilt fittings include an operating grip connected to a locking rod linkage concealed in the wing for controlling displacement of the wing with respect to the frame. Such fittings also include tilt shears disposed rotatably on the window or door frame, a corner bearing and at least two locking means disposed on the side of the swing axis and formed by a lock member secured to the linkage and a closure member secured to the window frame. Operation of the grip effects displacement of the concealed locking rod linkage from a first position, wherein the wing is secured in a closed state within the frame, to second and third positions for enabling the wing to be tilted about a bottom axis or to be swung about a side axis with respect to the frame. These positions are not discretely defined in that the grip, and accordingly the locking rod linkage, may be displaced a limited amount without changing the mode of operation of the wing. This limited displacement is sometimes referred to as a lost motion of the locking rods.
Conventionally, the linkage is constructed such that the operating grip is displaceable from a downwardly directed closure position into a horizontally directed tilt position and thereafter into an upwardly directed swing position. It is, however, possible to construct the linkage such that the grip is moved from the downwardly directed closure position through a horizontally directed swing position into an upwardly directed tilt position.
One disadvantage of known swing-tilt fittings is that the wing has only a single tilt position; that is, fully tilted. Generally, the tilt shears are provided to limit the degree of tilt of the wing and thereby define the fully tilted position. However, in most such fittings, a further disadvantage is that the tilt position is not secured so that the window or door wing can unintentionally slam shut.